The general objective of this contract is to assess the long-term effects of potent antiretroviral therapy (ART) on HIV-induced disease of the nervous system, focusing on the complete range of neurologic, neuropsychological, and neurobehavioral outcomes of ART therapy. The data collected from these studies will provide a resource for assessment of the impact of CNS infections on overall HIV-1 disease progression. This data resource is particularly significant, given the current intense interest in latent CNS reservoirs and the potential for reseeding of peripheral compartments by drug resistant strains of HIV-1. The Contractor shall initiate, manage and coordinate a cross sectional and longitudinal multi-site study of 5 years duration with adequate statistical power to address the above objective, in accordance with an approved protocol. The Contractor shall provide a paradigm for obtaining patient sampling size estimates in order to ensure that reliable conclusions with acceptable statistical power can be drawn from the data. The Government estimates that 4-6 sites will be utilized in this study, to assess 400-500 subjects per year, and that 10-20% of these subjects will be followed for a longer period of time. Sites shall be selected through a competition process, after award, with the concurrence of the NIMH. The Contractor will be responsible for central coordination including recruiting study sites, protocol development and finalizing the study design, preparing informed consent documents, providing data forms, training, centralized communication, data entry and management, quality control procedures, site monitoring, statistical analysis, report writing and other related activities. Procedures shall be developed for the collection, storage, retrieval and final disposition of patient samples. For subjects that are going to be followed, the Contractor will need to retain and store blood and plasma samples. The Contractor shall propose a centralized laboratory site to receive, process, and store study samples.